1. Field of the Invention
The present invention is broadly concerned with a coating and methods of applying the coating to agricultural grade fertilizer particles. The coating inhibits the adsorption and absorption of hydrocarbons into the pores of the fertilizer particles thereby reducing the efficacy of the fertilizer as an oxidizing source in the production of incendiary devices. More particularly, the invention is concerned with coatings containing at least one polymer and methods of applying the coating to fertilizer products. The invention has particular utility in the deterrence or prevention of agricultural grade fertilizers and industrial grade ammonium nitrate being used to create weapons of terror.
2. Description of the Prior Art
Some common agricultural grade fertilizers generally comprise compounds which serve as excellent oxidizing agents, ammonium nitrate being one such compound. Generally, the fertilizer particles contain pores into which a number of other chemical agents can infiltrate, including hydrocarbon materials. The combined ammonium nitrate/fuel infiltrated particle is commonly referred to as ANFO (ammonium nitrate fuel oil). The article “Blasting Products” of the ANFO Manual distributed by El Dorado Chemical Company (St. Louis, Mo.), a copy of which is submitted herewith, is hereby incorporated by reference. When supplied with an ignition source, the hydrocarbon material acts as a fuel that is oxidized by the fertilizer particles. The resulting chemical reaction can release considerable amounts of energy, especially when the reactants are present in substantial quantities. To be most effective as an explosive, the ANFO will comprise about 5.7% by weight fuel oil. It is understood that when alternative sources of hydrocarbon fuel are used the fuel:ammonium nitrate ratio may need to be altered to achieve a stoichiometrically balanced mixture.
Both hydrocarbon fuels and fertilizers are readily available and relatively inexpensive products thereby making them excellent raw materials for producing renegade incendiary devices. The Oklahoma City bombing incident is one tragic example of how such materials may be used to perpetrate large-scale, terrorist atrocities.
During the manufacturing process, fertilizer particles are coated with an anti-dusting agent in order to reduce the amount of fertilizer dust produced during handling of the particles.
A commonly used anti-dusting agent is Galoryl (Lobeco Products Inc., Lobeco, S.C.) which is hydrocarbon based and is sprayed on during the manufacturing process. Being hydrocarbon based, this coating does not inhibit the infiltration of other hydrocarbon materials that may be used in constructing an incendiary device. Additionally, the anti-dusting agent does not form a protective barrier film encapsulating the entire fertilizer particle thereby leaving numerous pores exposed.
In order to prevent the misuse of ammonium nitrate in improvised explosives, it is necessary physically separate the fuel from the ammonium nitrate and also prevent the penetration of the liquid fuel into the fertilizer particles. If the fuel does not enter the interior of a sufficient number of particles in an optimal amount, the utility of ammonium nitrate particles as an oxidizer is substantially reduced or completely eliminated. There is a real need in the art for a fertilizer particle coating which forms a barrier that inhibits hydrocarbon infiltration of the fertilizer pores, and which will not alter the effectiveness of the fertilizer for its intended agricultural applications.